Cleanup: Remove PPS RExt extension (and only remaining parameter cross-component prediction)

I tried to remove all dependent code. Required some reformatting to properly understand loops and conditionals.

All changes are enclosed in REMOVE_PPS_REXT

In CTC results are not completely finished. Zero difference for CTC.

(code should only have been active for 4:4:4 anyways, except for some PPS flags)

Note: After macro removal CrossCompPrediction.cpp/.h should be removed as well